Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.25.1 (proteasome)
 28,817 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The activities of four lysosomal and two nonlysosomal hydrolases were studied in skeletal muscle biopsy samples from patients with neuromuscular diseases and from controls. beta-Glucosaminidase activity was increased in polymyositis. beta-Glucuronidase and alkaline protease activities were elevated in muscular dystrophy in adults, whereas cathepsin D activity was increased in amyotrophic lateral sclerosis. There were significant correlations between the activities of lysosomal and nonlysosomal hydrolases. The activity of beta-glucuronidase, beta-glucosaminidase, alkaline protease, and dipeptidyl aminopeptidase IV showed a positive correlation with the severity of muscular atrophy. The activities of these hydrolases and the activity of dipeptidyl aminopeptidase I correlated positively with the activities of muscular galactosylhydroxylysyl glucosyltransferase and with the serum concentration of type III procollagen aminoterminal propeptide. The results suggest that in neuromuscular diseases the lysosomal and nonlysosomal pathways for muscle degradation are affected concomitantly with collagen biosynthesis.
Arch Neurol 1983 Sep
PMID:Lysosomal and nonlysosomal hydrolases of skeletal muscle in neuromuscular diseases. 635 16

Pseudomonas aeruginosa elastase, but not alkaline protease, degraded pooled, normal, human IgG in vitro and this degraded IgG lost its protective effect when used to treat burned, P. aeruginosa infected mice. Plasma IgG levels in burned, uninfected mice declined immediately postburning, but remained relatively constant thereafter; the levels in burned, P. aeruginosa infected mice continued to decline until death ensued. Infection of burned mice with an elastase+ strain caused the IgG decline, while infection with an elastase- strain did not, suggesting that elastase production caused the in vivo decline in plasma IgG. Local treatment with the protease inhibitor alpha 2-macroglobulin, of burned mice infected with an elastase+ organism, reduced the IgG decline observed in control mice. These data support the hypothesis that P. aeruginosa elastase acts as an IgG protease both in vitro and in vivo and gives insight into how this enzyme may act as a virulence factor in P. aeruginosa.
Can J Microbiol 1984 Sep
PMID:Experimental studies of the pathogenesis of infections owing to Pseudomonas aeruginosa: elastase, an IgG protease. 643 5

Interactions between protein components of the chemotaxis mechanism in Escherichia coli were investigated by using the cleavable cross-linking reagent, dithiobis(succinimidyl propionate). Two methods were used to allow detection of chemotaxis-specific proteins in intact cells. The first method was to program their synthesis in the presence of [35S]methionine using lambda E. coli hybrid phages which carry the chemotaxis genes. The second method was to label endogenous methyl-accepting chemotaxis proteins (MCP's), with the methyl donor S-adenosyl-L-[methyl-3H]methionine, after permeabilizing the cells with EGTA. Physical associations between proteins were analyzed, after cross-linking, by two dimensional NaDodSO4-polyacrylamide gel electrophoresis. Both labeling methods demonstrate that MCP I and MCP II exist as functional tetramers. Other proteins involved with chemotaxis were found to form dimers and higher polymers. Phage-directed products of cheW, cheX, motA, and cheA formed dimers. CheB and hag products formed multimers. A number of apparent interactions between different gene products were detected as well. Products of cheB, cheW, cheZ, motA, and motB were found to form complexes with other gene products. Included are results consistent with interactions between the products of cheB and cheZ.
Biochemistry 1980 Sep 30
PMID:Chemotaxis in Escherichia coli: associations of protein components. 644 31

Caulobacter crescentus carries a flagellum and is motile only during a limited time in its cell cycle. We have asked if the biochemical machinery that mediates chemotaxis exists coincident with the cell's structural ability to respond to a chemotactic signal. We first demonstrated that one function of the chemotaxis machinery, the ability to methylate the carboxyl side chains of a specific set of membrane proteins (methyl-accepting chemotaxis proteins, MCPs), is present in C. crescentus. This conclusion is based on the observations that (i) methionine auxotrophs starved of methionine can swim only in the forward direction (comparable to smooth swimming in the enteric bacteria), (ii) a specific set of membrane proteins was found to be methylated in vivo and the incorporated [3H]methyl groups were alkali sensitive, (iii) this same set of membrane proteins incorporated methyl groups from S-adenosylmethionine in vitro, and (iv) out of a total of eight generally nonchemotactic mutants, two were found to swim only in a forward direction and one of these lacked methyltransferase activity. Analysis of in vivo and in vitro methylation in synchronized cultures showed that the methylation reaction is lost when the flagellated swarmer cell differentiates into a stalked cell. In vivo methylation reappeared coincident with the biogenesis of the flagellum just prior to cell division. In vitro reconstitution experiments with heterologous cell fractions from different cell types showed that swarmer cells contain methyltransferase and their membranes can be methylated. However, newly differentiated stalked cells lack methyltransferase activity and membranes from these cells cannot accept methyl groups. These results demonstrate that MCP methylation is confined to that portion of the cell cycle when flagella are present.
Proc Natl Acad Sci U S A 1983 Sep
PMID:Methylation involved in chemotaxis is regulated during Caulobacter differentiation. 657 21

Using a modification of the EGTA treatment of Oishi and Smith [Oishi, M., & Smith, C. L. (1978) Proc. Natl. Acad. Sci. U.S.A. 75, 3569], Escherichia coli cells have been made permeable to S-adenosylmethionine and other related molecules in order to facilitate the study of methylation in chemotaxis. The permeable cells are nonmotile but respond to chemotactic stimuli by reversible methylation of their methyl-accepting chemotactic proteins (MCP I and MCP II) in a manner similar to that of untreated, motile cells. Addition of S-adenosyl-L-[methyl-3H]methionine to the permeable cells specifically labels two proteins, MCP I and MCP II. Methylation of these MCP's is dependent on the presence of wild-type gene products of flaI, flaA, cheB, cheX, tsr, and tar. The extent of methylation of the MCP's is affected by the presence of attractants or repellents: addition of attractant increases the steady-state level of methylation; addition of repellent causes rapid demethylation to a new steady-state level. Methylation is inhibited by the addition of the transmethylase inhibitors A9145C and Sinefungin, which are S-adenosylmethionine analogues, and by S-adenosylhomocysteine.
Biochemistry 1980 Sep 30
PMID:Methylation of chemotaxis-specific proteins in Escherichia coli cells permeable to S-adenosylmethionine. 677 92

The central distribution of visceral primary afferent fibers from the pelvic nerve of the cast and the relationship of these fibers to preganglionic neurons of the sacral parasympathetic neurons (SPN) have been studied. Horseradish peroxidase (HRP) applied to the cut pelvic nerve was detected ipsilaterally in preganglionic neurons and dorsal root ganglion cells (segments S1-S3), and in central afferent projections to Lissauer's tract (LT), the dorsal columns, the dorsolateral funiculus, and spinal gray matter. The afferent projections were strongest in the region of the SPN (S1-S3) but extended far beyond its limits (e.g., LT was labeled from L4 to Cx7). In the transverse plane, collateral fiber bundles formed a thin shell around the dorsal horn predominantly within lamina I and expanded into terminal fields in the gray matter. The more prominent lateral collateral projection (LCP) extended into laminae V and VI, whereas the medial one (MCP) ended in the dorsal commissure. In longitudinal planes these projections exhibited a periodicity with an interval of approximately 200 micrometer. The distribution of afferent collateral projections overlaps the regions where many preganglionic neurons and their dendritic extensions are located, and also areas known to contain interneurons involved in visceral pathways. A differential distribution of afferents within the SPN was noted where a higher intensity was observed in proximity to those neurons located in laminae V and VI, which innervate the colon, and a lower intensity near neurons located in Lamina VII which innervate the bladder. This is consistent with the known spinal control of colon reflexes and the supraspinal control of bladder reflexes. The widespread rostrocaudal extent of the pelvic primary afferent projection is consistent with the necessity for the integration of somatic and autonomic elements from various levels of the lumbo-sacral-coccygeal spinal cord in the performance of pelvic visceral functions.
J Comp Neurol 1981 Sep 20
PMID:The distribution of visceral primary afferents from the pelvic nerve to Lissauer's tract and the spinal gray matter and its relationship to the sacral parasympathetic nucleus. 727 58

Human gametes and pre-implantation embryos express selectively several complement regulatory proteins. Membrane cofactor protein (MCP, CD46) and decay accelerating factor (DAF, CD55) are regulators for C3 convertases and protectin (CD59) is an inhibitor of the membrane attack complex. These three proteins were identified on human sperm and found to be functional. CD55 and CD59 were both expressed by the plasmic membrane of unfertilized oocytes and pre-implantation embryos. CD46 was not present on unfertilized oocytes but appeared at the 6/8 cell-stage embryo when human gene expression first occurs. Complement receptor 1 (CR1, CD35) and MHC class I antigens were not found on oocytes neither on embryos. Such a selective expression of complement regulatory proteins associated with the lack of MHC class I antigens may represent an immune protective mechanism by which human gametes and pre-implantation embryos escape from complement-mediated damage during their travel through the female genital tract. Indeed uterine, tubal and follicular fluids contain all the components of the complement cascade, including classical and alternative pathways. Nevertheless participation of CD46 and CD59 in cell to cell interaction during fertilization and/or implantation cannot be excluded. CD59 is an adhesive molecule involved in the rosette phenomena and CD46 has been described as the human receptor for measles virus, which binds through a fusion protein. Monoclonal antibodies raised against these two proteins (CD46 and CD59) are able to inhibit heterospecific fertilization between zona-free hamster oocytes and human spermatozoa suggesting the role of these proteins during fertilization.
Contracept Fertil Sex 1995 Sep
PMID:[Expression and role of complement regulatory proteins on human gametes and pre-implantation embryos]. 749 32

Complement in the human respiratory tract protects the host from invading microorganisms and from other inhaled insults. However, complement may also lyse the host's respiratory tract cells, leading to tissue injury. In many extrapulmonic tissues, cells express cell-membrane complement regulatory glycoproteins that protect the cells from complement-induced lysis. To determine whether these glycoproteins are expressed in human respiratory tract tissue, we studied tissue biopsies of healthy and diseased human respiratory tract from nose to alveoli for the presence of four cell-membrane complement regulatory glycoproteins (membrane cofactor protein [MCP], decay-accelerating factor [DAF], CD59, and complement receptor type 1 [CR1]) using an immunoperoxidase technique. In addition, to establish a model for in vitro studies of these glycoproteins in respiratory cells, we studied whether they are expressed in cultured nasal epithelial cells, using the same technique. Altogether, 26 tissue specimens from 22 patients were studied. We found that normal human respiratory tract from nose to alveoli express MCP, DAF, and CD59, but not CR1, and that this expression increases in inflammation and in lung cancer. In addition, expression in nasal epithelial cells is retained under cell culture conditions. These findings suggest that human respiratory tract tissue may regulate complement activation on its surface in order to avoid self-injury. We propose that imbalances in the mechanism that regulates cell-membrane complement may predispose the respiratory tract to tissue injury and disease, and that iatrogenic modulation of such imbalances may help to prevent these adverse consequences.
Am J Respir Crit Care Med 1995 Sep
PMID:Expression and distribution of cell-membrane complement regulatory glycoproteins along the human respiratory tract. 754 58

We have identified and characterized a specific nuclease activity to be tightly associated with proteasomes. Using tobacco mosaic virus RNA (TMV-RNA) as substrate to analyze and quantify the cleavage reaction, we supply several lines of evidence that this nuclease activity is an integral part of proteasomes. Thus, RNase activity was coincident with the elution profiles of proteasomes at each stage of purification. Proteasomal nuclease activity was resistant to strong dissociation conditions using 480 mM KCl, 0.5% sodium lauroylsarcosinate, and 6 M urea. This nuclease activity remained associated with an urea-resistant subcomplex of the proteasome comprising a specific set of proteins. Finally the digestion of TMV-RNA led to a well defined pattern of RNA fragments while 5 S ribosomal RNA and globin mRNA were not degraded. These results provide further evidence that proteasomes are able to discriminate between different RNAs, and the possible involvement of proteasomes in translation control is discussed.
J Biol Chem 1995 Sep 15
PMID:Identification and initial characterization of a specific proteasome (prosome) associated RNase activity. 754 75

We have identified and purified an endogenous inhibitor of multicatalytic proteinase (MCP) from human erythrocyte membranes. The inhibitor showed a molecular mass of 90 kDa on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The inhibitor protein was purified from the erythrocyte membranes using Heparinagarose and hydroxylapatite chromatography and the size exclusion on a Biogel A 1.5 m column in the presence of high salt. The 90-kDa protein inhibited all three peptidase activities of MCP; trypsin-like, chymotrypsin-like and peptidyl glutamyl peptide hydrolyzing (PGPH). However, it failed to cause any significant inhibition of caseinolytic activity of MCP, suggesting that the regulation of proteinase and peptidase activities is distinct. The inhibition of the chymotrypsin-like activity was noncompetitive. The results suggest that the 90-kDa inhibitor protein may be an important regulator of membrane-bound MCP.
Biochem Biophys Res Commun 1995 Sep 25
PMID:Identification and purification of a 90-kDa membrane-bound endogenous inhibitor of multicatalytic proteinase from human erythrocytes. 757 69


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